Oklahoma DOT E&SC Workshop June 13, 2016 Module 2: BMPs for Linear Projects 1 Erosion & Sediment Control Workshop Best Management Practices (BMPs) for Linear Transportation Projects Erosion & Sediment Control Workshop Perimeter Control Devices Runoff Conveyance Measures Velocity Control Treatments Drain Inlet/Catch Basin Controls Sediment Containment Systems Erosion & Sediment Control Workshop Perimeter Control Devices
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Erosion & Sediment Control Workshop Best Management Practices … · 2018-08-10 · Oklahoma DOT E&SC Workshop June 13, 2016 Module 2: BMPs for Linear Projects 2 Erosion & Sediment
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Oklahoma DOT E&SC Workshop June 13, 2016
Module 2: BMPs for Linear Projects 1
Erosion & Sediment Control Workshop
Best Management Practices (BMPs)
for Linear Transportation
Projects
Erosion & Sediment Control Workshop
Perimeter Control DevicesRunoff Conveyance MeasuresVelocity Control TreatmentsDrain Inlet/Catch Basin ControlsSediment Containment Systems
Erosion & Sediment Control Workshop
Perimeter Control Devices
Oklahoma DOT E&SC Workshop June 13, 2016
Module 2: BMPs for Linear Projects 2
Erosion & Sediment Control Workshop
Safety Fence •Polyethylene or polypropylene orange fencing
•Installed along the outside riparian buffer, wetland, or water boundary located within the construction corridor
•Installed prior to ANYland disturbance
•Conform to theground contours
•Wood or steel posts
Erosion & Sediment Control Workshop
Gravel Construction Entrance •2-5” stone placed on filter fabric
•Approximately 50’ long and 12’ wide
•Allow adequate turning radius for trucks
•Minimizes tracking ofsoil onto pvmt
•Supplement stone
Erosion & Sediment Control Workshop
Temporary Silt Fence•Reduces water flow and retains sediment on-site
•Overlap splice joints 18 inches
3-6 ft
Optional outlet using Special Sediment Control
Fence (Max width=6 ft)
Oklahoma DOT E&SC Workshop June 13, 2016
Module 2: BMPs for Linear Projects 3
Erosion & Sediment Control Workshop
Special Sediment Control Fence
• Reduces water flow and retains sediment
• Used where flows and sediment loads will be too great for silt fence
Erosion & Sediment Control Workshop
Special Sediment Control Fence
Erosion & Sediment Control Workshop
Special Sediment Control Fence
Fold in 4 ft. wire mesh
(24 gauge--1/4-in. opening)
• Not to be placed in areas determined to be wetlands without proper permits
Oklahoma DOT E&SC Workshop June 13, 2016
Module 2: BMPs for Linear Projects 4
Erosion & Sediment Control Workshop
Special Sediment Control Fence
Erosion & Sediment Control Workshop
Temporary Silt Ditch• Small ditch or channel that
directs runoff from project perimeter into a basin, or rock filter dam
• 2:1 side slopes• 1 ft deep
TSD
Erosion & Sediment Control Workshop
Temporary Silt DitchTSD
Stabilized
1 ft. deep
Oklahoma DOT E&SC Workshop June 13, 2016
Module 2: BMPs for Linear Projects 5
Erosion & Sediment Control Workshop
Temporary Silt DitchTSD
• Problems– Ditch too deep– Walls too steep– Runoff bypasses ditch
Erosion & Sediment Control Workshop
Temporary Diversion
• Excavated channel that directs runoff into a sediment control structure
• 2:1 side slopes
• Minimum depth 1ft 6in
TD
Erosion & Sediment Control Workshop
Temporary DiversionTD
Stabilized
Oklahoma DOT E&SC Workshop June 13, 2016
Module 2: BMPs for Linear Projects 6
Erosion & Sediment Control Workshop
Temporary DiversionTD
Erosion & Sediment Control Workshop
Temporary Diversion• Problems
– Channel walls too steep– Channel too deep– Channel too steep
TD
Erosion & Sediment Control Workshop
Temporary Diversion
Oklahoma DOT E&SC Workshop June 13, 2016
Module 2: BMPs for Linear Projects 7
Erosion & Sediment Control Workshop
Runoff Conveyance Measures
Erosion & Sediment Control Workshop
Temporary Slope Drain with Earthen Berm
• Carries concentrated runoff down a cut or fill slope without causing erosion
• 12 in diameter flexible pipe
• Sediment storage must be provided at top of slope near inlet or at outlet if slope drain discharges directly offsite w/o basin or trap
Ideal spacing - base of the upstream dam is not higher than the top of the downstream dam
Temporary Rock Silt Check –Type B
Oklahoma DOT E&SC Workshop June 13, 2016
Module 2: BMPs for Linear Projects 12
Erosion & Sediment Control Workshop
Temporary Rock Silt Check –Type B
Erosion & Sediment Control Workshop
Temporary Rock Silt Check –Type B
• Maintenance– Remove sediment when ½ the dam height is
reached
Erosion & Sediment Control Workshop
Temporary Rock Silt Check –Type B
• Problems– Center of the dam should be lower than the edges– Properly key in dam to channel banks– Lacking weir section in center of structure
Oklahoma DOT E&SC Workshop June 13, 2016
Module 2: BMPs for Linear Projects 13
Erosion & Sediment Control Workshop
Temporary Rock Silt Check-Type A
• Small dam with weir outlet
• Constructed of Class B Rip-rap and Sediment Control Stone
• Usage – Outlet of slope drain– In ditches and channels– Can lead off-site
• Naturally formed storage area traps sediment
Erosion & Sediment Control Workshop
Wattles/Fiber Check Dams• Substitute for Type B Rock Silt Check
• Usage adjacent to Trout Waters and other Environmentally Sensitive Areas (ESAs)
• Involve application of Polymer to aid in turbidity reduction of project runoff
Erosion & Sediment Control Workshop
Wattles/Fiber Check Dams
Oklahoma DOT E&SC Workshop June 13, 2016
Module 2: BMPs for Linear Projects 14
Erosion & Sediment Control Workshop
Wattles/Fiber Check Dams
Erosion & Sediment Control Workshop
Drain Inlet/Catch Basin Controls
Erosion & Sediment Control Workshop
Rock Pipe Inlet Sediment Trap –Type A & B
• Prevents sediment from entering pipe structure
• Receives water from more than one direction
°
°°°°°°
°°°°
Oklahoma DOT E&SC Workshop June 13, 2016
Module 2: BMPs for Linear Projects 15
Erosion & Sediment Control Workshop
Rock Pipe Inlet Sediment Trap –Type B
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°°°°°°
°°°°
Class A
Erosion & Sediment Control Workshop
Rock Inlet Sediment Trap –Type A & B
°°°°
°
° °°°°°°
°° °°A
• Stone dam built around a drop inlet
• Slows flow creating a pool for settling of sediment
Erosion & Sediment Control Workshop
Rock Inlet Sediment Trap – Type A°°°°
°
° °°°°°°
°° °°A
Class B Stone
Oklahoma DOT E&SC Workshop June 13, 2016
Module 2: BMPs for Linear Projects 16
Erosion & Sediment Control Workshop
Rock Inlet Sediment Trap –Type C
• Small protective structure around an inlet that receives light to moderate flow
• Slows flow creating a pool for settling of sediment
• Can be locatedwithin 30 ft oftravel lane
°°°°
°
° °°°°°°
°° °°C
Erosion & Sediment Control Workshop
Rock Inlet Sediment Trap – Type C°°°°
°
° °°°°°°
°° °°C
Erosion & Sediment Control Workshop
Rock Inlet Sediment Trap –Type C
°°°°
°
° °°°°°°
°° °°C
• Problems– Improper installation– Use of silt fence in place of stone– Lack of stone around structure
Oklahoma DOT E&SC Workshop June 13, 2016
Module 2: BMPs for Linear Projects 17
Erosion & Sediment Control Workshop
Rock Inlet Sediment Trap –Type C
• Problems
°°°°
°
° °°°°°°
°° °°C
Erosion & Sediment Control Workshop
Summary-Rock Inlet Sediment Traps
°°°°
°
° °°°°°°
°° °°B
1632.02
°°°°
°
° °°°°°°
°° °°A
1632.01
°°°°
°
° °°°°°°
°° °°C
1632.03
Type A Type B Type C
Structure Material Class B Class A
Hardware cloth/t-post
Sediment control stone Yes Yes YesDist. from travel lane >30 ft. <30 ft. <30 ft.Min. volume 3600 ft3/ac 3600 ft3/ac 3600 ft3/ac
Erosion & Sediment Control Workshop
BMPs must be 1. installed correctly2. inspected often3. maintained as needed to work effectively.
BMP’s should be inspected before and after rainfall events.
Oklahoma DOT E&SC Workshop June 13, 2016
Module 2: BMPs for Linear Projects 18
Erosion & Sediment Control Workshop
Sediment Containment Systems
Erosion & Sediment Control Workshop
ODOT Sed Basin Detail
Erosion & Sediment Control Workshop
Temporary Silt Basin – Type B• Collects sediment flowing through a
drainage way• Used with rock silt checks to slow flow
Oklahoma DOT E&SC Workshop June 13, 2016
Module 2: BMPs for Linear Projects 19
Erosion & Sediment Control Workshop
Temporary Silt Basin – Type B
Erosion & Sediment Control Workshop
Temporary Silt Basin – Type B
Erosion & Sediment Control Workshop
Temporary Rock Sediment Dam – Type B
• Small dam with weir outlet and built-in sediment basin
• Traps sediment prior to runoff leaving the site• Must meet minimum dimensions listed on plans
for L x W x D and weir Length• Built above grade
Oklahoma DOT E&SC Workshop June 13, 2016
Module 2: BMPs for Linear Projects 20
Erosion & Sediment Control Workshop
Riser Basin• Captures runoff before leaving site • Perforated riser pipe drains the basin• Overflow spillway for runoff exceeding
riser capacity
Erosion & Sediment Control Workshop
Riser Basin
Erosion & Sediment Control Workshop
Riser Basin
Oklahoma DOT E&SC Workshop June 13, 2016
Module 2: BMPs for Linear Projects 21
Erosion & Sediment Control Workshop
• Serves large drainage areas with concentrated flows where other BMPs are inadequate
• Storage area of 1800 cu ft/disturbed ac
Riser Basin
Erosion & Sediment Control Workshop
• Common Problems– Outlet pipe not protected– Lack of maintenance– Steep inlet channels generating sediment– Drainage bypasses basin
Riser Basin
Erosion & Sediment Control Workshop
Flashboard Riser Outlet
• Adjustable standing pool
• Can empty for sediment removal
Oklahoma DOT E&SC Workshop June 13, 2016
Module 2: BMPs for Linear Projects 22
Erosion & Sediment Control Workshop
Water Level
Flashboard Riser
Solid Earthen Dam
RemovableStop Logs
Gravel Fill for Riser Access
Isolated View
Cross-sectional View
Example of a Flashboard Riser Installation
Erosion & Sediment Control Workshop
COIR FIBER BAFFLE
Erosion & Sediment Control Workshop
Porous Baffle Spacing
• Baffles in Silt Basins at drainage turnouts and all other temporary rock sediment dams—Type-A and -B:– If basin length ≤ 10 feet; 1 baffle. (State
Forces Projects)– If basin length > 20 feet; 3 baffles.– If basin length between 10 -20 feet; 2
baffles.
Oklahoma DOT E&SC Workshop June 13, 2016
Module 2: BMPs for Linear Projects 23
Erosion & Sediment Control Workshop
How many porous baffles are needed and what is their spacing
if the basin is :A.) 8 ft long?B.) 18 ft long?C.) 48 ft long?
Basin Length
Erosion & Sediment Control Workshop
Surface Outlet (Skimmer)• Skimmer is a dewatering device• Primary dewatering during a storm event occurs
over the emergency spillway.• Opening in ‘C’ points towards the dam
Erosion & Sediment Control Workshop
Skimmer Basin with Baffle
Oklahoma DOT E&SC Workshop June 13, 2016
Module 2: BMPs for Linear Projects 24
Erosion & Sediment Control Workshop
Emergency Spillway•Line with Type 2 filter fabric for drainage•Overlap seams 18 inches•Secure edges in 5” deep trench and compact•Secure fabric with 6” metal staples; 3 ft spacing•Size weir length (width) per plan•Significant rain should activate emergency spillway
Weir Length (Width)
Erosion & Sediment Control Workshop
Skimmer Basin with Baffle
Erosion & Sediment Control Workshop
Skimmer Basin with Baffle
Oklahoma DOT E&SC Workshop June 13, 2016
Module 2: BMPs for Linear Projects 25
Erosion & Sediment Control Workshop
Skimmer Basin with Baffle
Erosion & Sediment Control Workshop
Skimmer Basin with Baffle
Erosion & Sediment Control WorkshopSkimmer•Minimum barrel diameter = 4 inches•Ensure orifice is sized per plan
-Example: 4-inch skimmer with 3.6-inch orifice -Contractor must insert “knock out plug” with 3.6 inch hole drilled in it into the 4 inch orifice
Orifice
Knock out plug
Oklahoma DOT E&SC Workshop June 13, 2016
Module 2: BMPs for Linear Projects 26
Erosion & Sediment Control Workshop
Maintenance• Clean out sediment at ½ design capacity